Visual Evaluation of Scatter Correction
Using Clinical Images○ Keisuke Kashima, Sakiko Himeji, Koji Oogari,
Kohei Yamaoka, Ryu Mabuchi, Kyoji Higashimura
Division of Clinical Radiology Service, Kyoto University Hospital

Disclosure of conflict of interest
We have nothing to declare for this study.

The 73rd Annual Meeting of the JSRT
Japanese Society of Radiological Technology

BackgroundA software-based scatter correction (SC) method has
been developed that is designed to restore image
contrast of non-grid images in a manner comparablewith an anti-scatter grid.
Grid(+), 90kV, 0.8mASGrid(-), 90kV, 0.4mAs, SC(-) Grid(-), 90kV, 0.4mAs, SC(+)

Radiat. Prot. Dosim. 2016, 169: 60-67

Background
Several works evaluate the physical characteristics of SCwith phantom study.
ECR 2015, DOI: 10.1594/ecr2015/C-1834
ECR 2016, DOI: 10.1594/ecr2016/C-0416

SC offers an alternative to the usage of an grid for
bedside chest radiography in terms of contrast improvement.
Radiat. Prot. Dosim. 2016, 169: 308-312

Even though image quality of SC chest X-ray does not
fully reach the level of grid(+) images, SC have potentialof the significant reduction of ~50 % in patient dose.
Radiat. Prot. Dosim. 2016, 169: 60-67

Purpose
To investigate the utility of scatter correction applied
to clinical images especially infant chest andadult knee joint using visual evaluation

Materials
X-ray systems
RADspeed Pro (SHIMADZU)

X’sy Pro (SHIMADZU)

Flat panel detector
CXDI-701C, 801C Wireless (CANON)

Image processing software
CXDI Control Software NE Ver. 2.15 (CANON)

MonitorRadiForce GS521 (EIZO)Image acquisition | Infant chestPatients
30 infants (mean: 2.3 yo, range: 0-5 yo)

X-ray exposure parameters
kVpmA
mAs

55 - 65250
1.25 - 3.50

SID (cm)

120 - 200

Scatter correction factor
without and ‘1’ (max= 10)

Image acquisition | Adult knee joint
Patients
30 (Right: 14, Left: 16)

X-ray exposure parameters
kVpmA
mAs

55 - 58125
4.0 - 5.0

SID (cm)

120

Scatter correction factor
without and ‘1’ (max= 10)

Visual Evaluation
Six radiological technologists subjectively assessed theimage quality with SC compared to w/o SC as following
grades.
-2-1012Bad
Somewhat badEquivalent
Slightly goodGood

Wilcoxon signed rank sum test was performed.
P value <0.05 was considered statistically significant.

Visual Evaluation | Infant chest• Mediastinal lines• Both pulmonary artery markings andbronchus shadow of the hilar region• Pulmonary markings of retrocardiac area

• Graininess• Sharpness• Contrast• “Impressive” overall image quality
JSRT 1992, 48 (4), 616-624

Visual Evaluation | Adult knee joint• Sharpness of trabeculae• Graininess of soft tissue• Margin of patella• Contrast• “Impressive” overall image quality

E.g. | Retrocardiac

Without SC

With SCE.g. | Margin of patella

Without SC

With SC

Results | Infant chest
ObjectMean (95% CI)

SDMax

Min

Mediastinal lines
Pulmonary artery,bronchus shadow
Retrocardiac

0.56 (0.49–0.63)

0.50 1.00

0.00

0.53 (0.46–0.61)

0.52 1.00 -1.00

0.57 (0.49–0.64)

0.50 1.00

Graininess-0.01 (-0.08–0.06)

0.48 1.00 -1.00

Sharpness

0.54 (0.46–0.61)

0.51 1.00 -1.00

Contrast

0.42 (0.33–0.52)

0.64 2.00 -1.00

Overall image quality

0.52 (0.42–0.61)

0.64 2.00 -1.00

CI = confidence interval; SD = standard deviation

0.00

Results | Infant chest
Mediastinal lines
1.0

Overall image
quality

0.50.0Pulmonary artery,bronchus shadow-0.5-1.0

Contrast

Sharpness

Retrocardiac* Graininess* : N.S.

Results | Adult knee joint
ObjectMean (95% CI)

SD Max Min

Sharpness of trabeculae

0.86 (0.79–0.93)

0.48 2.00 -1.00

Graininess of soft tissue-0.41 (-0.50–-0.31)

0.67 1.00 -2.00

Margin of patella

0.32 (0.23–0.41)

0.60 2.00 -1.00

Contrast

0.27 (0.14–0.39)

0.84 2.00 -2.00

Overall image quality

0.11 (-0.22–0.23)

0.86 2.00 -2.00

CI = confidence interval; SD = standard deviation

Results | Adult knee joint
Sharpness of trabeculae
1.00.5* Overall imagequality

0.0-0.5

Graininess ofsoft tissue-1.0

Contrast

Margin of patella* : N.S.

Discussion
SC improved image quality even with dose
for non-grid X-ray.
• Increased dose is no need.
• SC may be applied to other subject.
(e.g. infant abdomen and chest-abdomen)• Image quality improvement is limited becauseof only applying SC without dose adjustment.

Discussion
Degradation of graininess• SC led to contrast enhancement,
but noise component was not removed.
• Simultaneous use of noise reduction processing
is required.
• Balance between SC image quality and noise levelshould be considered.

Conclusions• Scatter correction with same dose fornon-grid X-rays can improve image qualityof infant chest and adult knee joint X-rays.
• Scatter correction is clinically useful.